Gram Negative Bacteria - Lesture 5 Flashcards
What are four classiications of gram negative bacteria?
Cocci
Bacilli
Coccobacilli
Pleiomorphic
What morphology is Neisseria sp?
Cocci - gram negative
What morphology is Bordatella pertussis?
Bacilli - gram negative
What morpology is Haemophilus influenza?
Coccobacilli - gram negative
What morphology is Yersinia pestis?
Coccobacilli - gram negative
What morphology is Chlamydia sp?
Coccobacilli - gram negative
What morphology is Legionlla pneumophile?
Pleiomorphic - gram negative
What morphology is Rickettsia sp?
Pleiomorphic - gram negative
Give characteristics of Neisseria sp? Morphology Oxygen tolerance Are the pathogens: Catalase positive or negative? Oxidase positive or negative?
Diplococci ‘coffee bean’ shape
Obligate aerobes
Pathogens are:
Catalase and oxidase positive
What are two human pathogens of the Neisseria sp?
N. gonorrhoeae - gonorrhea
N. meningitidis - meningococcal meningitis
Neisseria gonorrhoeae characteristics?
Acapsular Many plasmids (genetic variability) Facultatively intracellular
What percentage of people (men/female) infected with Neisseria gonorrhoeae are asymptomatic
10% of males
80% of females
Which bacterial infection has the following clinical features?
Purulent, foul-smelling discharge
Inflammation, dysuria, urethritis
Conjunctivitis (newborns)
Septicemia leading to endocarditis, meningitis, gonococcal dermatitis-arthritis syndrom (arthralgia, tenosynovitis, dermatitis)
Neisseria gonorrhoeae
What is the incubation period of Neisseria gonorrhoeae?
2-14 days
What bacterial infection has the following virulence:
No exotoxin - autolysis releases virulence factors
Lipooligosaccharide (LOS) slightly different in structure from LPS
Opa proteins:
-promote adherence
-multiple expressed by on bacterium (phase variation
Cyclical expression inhibits antibody binding and immunological memory
Neisseria gonorrhoeae
How is Neisseria gonorrhoeae transmitted?
sexual/mucousal
- Neonatal infection during birth - prenatal screening is important
- Reinforcement due to lack of development of immunological memory
What is the treatment for Neisseria gonorrhoeae?
Traditionally - Penicillin, tetracycline, ceftriaxone - increase in drug resistants require stronger/additional antibiotic approaches
Combination therapy common - ceftriasone + doxycyline
Public health monitoring of drug resistance important
What is a sequelau of untreated gonorrhea and chlamydia in women?
Pelvic inflammatory disease
Describe pelvic inflammatory disease including symptoms and what it can lead to if untreated
Inflammation of the uterus, fallopian tubes, ovaries
Range of symptoms but many are asymptomatic
Lower abdominal pain, fever, cervical motion tenderness, cervical inflammation
Untreated –> infertility, ectopic pregnancy, blocked fallopian tubes, miscarriage or premature birth
What can Neisseria gonorrhoeae lead to in males?
Epididymitis that may lead to infertility
Characteristics of Neisseria meningitidis (meningococcal disease)
Capsular - multiple serotypes based on capsular antigens (A, B, C, Y, W135)
No plasmids
Facultatively intracellular
What bacterial infection displays the following clinical features:
Commonly asymptomatic - carries may spread pathogen via respiratory droplets
_____ septicemia leads to DIC and hemorrhage - severe skin rash (severe cases require amputation)
_____ CNS invasion leads to meningitis - fever, altered mental status, neurological symptoms (convulsions, coma)
High mortality rate if untreated
2nd most common cause of bacterial meningitis in children, adults
most common cause of bacterial meningitis in teens/young adults
Neisseria meningitidis
What are the virulence factors of Neisseria meningitidis
Capsule - antiphagocytic
LOS - endotoxin
How is Neisseria meningitidis transmitted?
How does the disease typically occur in a population? what serotype is in Canada?
Respiratory droplets
Disease occurs as outbreaks - serotype C in Canada
What is the uncubation period of Neisseria meningitidis
2-10 days
What is the treatment and prevention of Neisseria meningitidis?
Vaccine for most human strains
Serotype C is vaccine-preventable
Treatment and hospitalization should occur immediately - drugs administered upon suspicion of infection
Penicillin G, cephalosporins + supportive treatment (IV fluid, oxygen, management or intracranial pressure, etc)
Characteristics of Bordatella pertusis (Whooping cough)
Gram negative coccobacillus, appears singly or in pairs
Colonizes URT and alveolar macrophages, leading to invasion
Pertussis toxin an important virulence factor
What bacterial infection has the following clinical features:
Early (catarrhal) stage - fever, mild coughing, sneexing, or runny nose, which increase in intensity (~10 days)
Late (paroxysmal) stage - uncontrollable fits, each with five to ten forceful coughs, followed by high-pitched “whoop” (~2-8 weeks or longer)
Bordatella pertusis
How is a diagnosis made of Bordatella pertusis?
Clinical symptoms and culture from nasal swab
How is Bordatella pertusis transmitted?
highly contagious by contact and respiratory droplets
What is the incubation period of Bordatella pertusis
5-20days
what is the treatment of Bordatella pertusis
Only effective at catarrhal stage
Macolide antibiotics administered to prevent complications
Vaccine available (pentavalent or DTP)
Characteristics of Haemophilus influenza (bacterial influenza)
Gram negative coccobacillus
Encapsulated (a-f) and non-encapsulated strains
Most serotypes are OPPORTUNISTIC pathogens
What are the most pathogenic strains of Haemophilus influenza?
H.influenza serotype b (Hib) and non-typable Hi (NTHi) strains most pathogenic
What bacterial infection has the following clinical features:
Surface infections mild/asymptomatic
Invasive infections may cause pneumonia, bronchitis
Haemophilus influenza
Which strain is responsible for 95% of invasive Haemophilus influenza infections?
Hib
What are potential complications of Haemophilus influenza infections?
Epiglottitis
Meningitis
Bacteremia
Septic arthritis
How is Haemophilus influenza infection diagnosed?
Culture (from sterile body site), agglutination test
How is Haemophilus influenza infection transmitted?
Transmitted via direct contact, contaminated surfaces
What is the incubation period of Haemophilus influenza
unknown - estimated to be 2-10 days
What is the treatment for Haemophilus influenza?
Hib vaccine available (pentavalent vaccine)
Cephalosporins for severe infection, penicillins + b-lactamase inhibitors for milder infection
Characteristics of Yestinia pestis (plague)
‘Black death’
Gram negative coccobacillus
Facultative anaerobe
Which bacterial infection has the following clinical features:
Bubonic plague
Pneumonic plague
Septicemic plague
Yestinia pestis
Describe the bubonic plague as caused by Yestinia pestis
Sudden fever, chills, weakness, headache
Swollen lymph nodes (buboes”
Describe the pneumonic plague as caused by Yestinia pestis
Fever, chills, chest pain
Cough, respiratory distress, bloody or watery mucous
Describe the Septicemic plague as caused by Yestinia pestis
Fever, chills, extreme weakness
Multiorgan hemorrhage, vasculitis
May result from bubonic or pnuemonic plague
How is Yestinia pestis diagnosed?
Identification of clinical features (buboes), lab testins from infected tissue including blood or lymph
How is Yestinia pestis transmitted?
Bubonic - vector-borne (fleas)
Pneumonic - respiratory droplets
Transmission from infected animals, contaminated water
What is the incubation period of Yestinia pestis
2-6days
What is the treatment/prevention of Yestinia pestis
Mortality rate high unless treated early
Strptomycin, chloramphenicol
tetracycline, flouroquiones
Characteristics of Chlamydia sp?
Gram negative coccobacilli
Obligate intracellular bacteria
Elementary body infective, reticulate body replicative
Replicative from bacterium replicates intracellularly in reticulate bodies/inclusion bodies (replicates by binary fission for 1-3wks in a host cell)
Bacteria exocytosed from host cell as an elementary body
What are the two human pathogens of Chlamydia sp?
Chlamydia trachomatis
Chlamydia pneumoniae
What bacterial infection shows the following clinical presentation:
Urogenital infection:
one of the most common STIs in North America
Painful urination, increasing discharge
In women - pain/bleeding during/after sex, bleeding between periods
Rectal infection - discomfort, pain, bleeding, discharge
Oral infection typically asymptomatic, despite shedding
Infection in the eye may lead to conjuctivitis
Chlamydia trachomatis
What percentage of people (men/women) infected with Chlamydia trachomatis are asymptomatic?
50% of males
80-90% of females
What are some complications of Chlamydia trachmatis infections in men? in women?
Men - epididymitis, rectitis, non-gonococcul urethritis
In women - pelvic inflammatory disease (untreated)
How is Chlamydia trachomatis transmitted?
mucosal (sexual)
What is the incubation period of Chlamydia trachomatis?
poorly defined 2-3 weeks or longer
What is the treatment of Chlamydia trachomatis?
doxycycline, azithromycin
Describe trachoma infection (serovars A, B, BA & C)
Infection of the eye - leading cause of infectious blindness
Associated with poor sanitation, hygiene, water, and is a major disease of developing areas
How is trachoma infection (serovars A, B, BA & C) spread?
Spread by eye discharge (contact, clothing…) and eye-seeking flies (mechanical vector)
What can trachoma infection (serovars A, B, BA & C) lead to?
Corneal scarring, blindness
What is the incubation period of trachoma infection (serovars A, B, BA & C)
7-12 days
What is the treatment for trachoma infection (serovars A, B, BA & C)
tetracycline, azithromycin
How is chlamydia pneumonia transmitted?
Respiratory secretions
Which bacterial infection is described in the following:
Most people are exposed to pathogen by adulthood - often asymptomatic
Causes mild bronchitis/pneumonia in children, more sever invasive disease in adulthood (community acquired pneumonia aka CAP)
Often associated with mixed infections
chlamydia pneumonia
Which bacterial infection has the following clinical features:
Mild, URT symptoms or no symptoms in most cases
Severe cases progress to LRT infection 1-4wks collowing exposure
Persistent cough, malaise, headache a common distinguishing feature
Fever early in infection, absent during clinically relevant stage
chlamydia pneumonia
What is the treatment for chlamydia pneumonia?
If needed doxycycline and related are used
How is chlamydia pneumonia related to atherosclerosis?
INcreased incidence of seropositivity in patients with atherosclerosis
Isolation of bacteria from atherosclerotic lesions
Induction of atherosclrotic plaques in animal models of infection
Activation of ROS - damage, inflammation, remodeling
Characteristics of Legionella pneumophile (Legionnaires’ disease)
Gram negative pleiomorphic
Contaminated water breeds bacterial growth - water cooler towers, air conditioning systems, plumbing systems
Which bacterial infection has the following clinical features:
fever, chillis, cough
Muscle aches, headache, fatigue, ataxia (loss of coordination), diarrhea, vomiting
Pontiac fever less severe, resembles acute influenza virus infection, resolves spontaneously
Legionella pneumophile
What are potential complications of Legionella pneumophile
Respiratory or renal failure
Sepsis
How is Legionella pneumophile transmitted?
Transmission via aerosol, water (associated with poor ventilation and water treatment facilities - hotels, hot tubs, factories, nursing homes)
Not spread from person to person
What is the incubation period of Legionella pneumophile?
2-10 days
What are the treatments for Legionella pneumophile?
Quinolones, macrolides, tetracyclins
What are characteristics of Rickettsia sp?
Gram negative aerobic, pleiomorphic
Obligate intracellular parasite
Typhus, rocky mountain fever, rickettsialpox
Vector-borne infection
R. prowazekii source of eukaryotic mitochondria
How is Rickettsia typhi (Typhus) spread?
Spread by lice feces
Which bacterial infection is described as:
high fever, cough, chest rash, severe muscle pain
Dermal leasions 5-6dpi, chest and spreading to the rest of the body
Severe vasculitis and increased vascular permeability - leads to shock, acute respiratory distress
Rickettsia typhi (Typhus)
How is Rickettsia diagnosed?
Multiple criteria including exposure, history, clinical preenstation and serology
What is the incubation period of Rickettsia?
5-10 days
What is the treatment for Rickettsia?
Doxycycline, chloramphenicol
